It is known in the art relating to internal combustion (IC) engines to provide a single pressure oil system for lubricating all or most of the moving components that require lubrication. In the cylinder heads, these may include rocker arms, camshafts, valve lifters valves and other mechanisms, such as pushrods in some engines. In the cylinder block and crankcase are found cylinders, pistons, connecting rods and a crankshaft, as well as oil and water pumps and, sometimes, balance shafts. Camshaft chain or gear drives may also require lubrication.
A single lubrication or oiling system is generally used to lubricate all these components as well as to actuate hydraulic valve lifters and to cool the pistons. A low pressure oil pump is generally used to draw oil from a single sump in the oil pan, or lower part of the crankcase, and supply the oil under pressure to all the components needing pressure lubrication.
Development of an engine in which the valves are hydraulically actuated raised the possibility that an improved oiling system might be developed which would better serve the purposes of lubrication and actuation of hydraulic components of the engine. Accordingly, an improved engine oiling system for these purposes was desired.